Natural gas resources of the sedimentary basins in China

Since 1980s, oil and gas resource assessment in China has gone through five development stages. Resource assessment in different stages differs in data input, methodology and key parameters, resulting in significantly different conclusions on the oil and gas resource potential in China. The latest round oil and gas assessment in China was completed in 2005, with the following characteristics: (1) petroleum system analyses in superimposed sedimentary basins were conducted; (2) several methodologies were simultaneously used, including mass balance, geological analogy and statistical approach; (3) contrasting criteria areas were used to optimize the assessment parameters; and (4) not only resource in place but also recoverable resource were estimated for the assessment result. The assessment on 129 onshore and offshore basins indicates that the total aggregated mean conventional gas resource in China is 43.9 trillion cubic meters (tcm) or 1549 trillion cubic feet (tcf), including 26.9, 8.1 and 8.8 tcm in onshore, nearshore and southern South China Sea basins, respectively. The total recoverable conventional gas resource is around 27.5 tcm or 970 tcf, including 16.8, 5.3 and 5.4 tcm in onshore, nearshore and far offshore basins, respectively. Most of these resources are distributed in six areas, including the onshore Tarim, Ordos, Sichuan, Qidam and Songliao basins, and the offshore areas in the East China Sea and South China Sea.